Merge branch 'Remove_QT4_checks' into 'master'

Plugin-AlignMeshes

Plugin-Backup

Plugin-Color

Plugin-Components

Plugin-Datacontrol

Plugin-Decimater

Plugin-DeserializeScreenshotMetadata

Plugin-GaussCurvature

Plugin-HoleFilling

Plugin-INI

Plugin-InfoMeshObject

Plugin-InfoSkeleton

Plugin-InfoVolumeMeshObject

Plugin-IsotropicRemesher

Plugin-Laplace

Plugin-MaterialPicker

Plugin-MeanCurvature

Plugin-MemInfo

Plugin-Merge

Plugin-MeshCompare